Tim.... many thanks for keeping HamTV tx turned on.... I have built a SHORT BACKFIRE antenna that "sees" you a good 15dB above noise on an overhead pass INSIDE a plastic conservatory..... It doesn't need tracking!
Keep up the good work........
de Mike in Minehead
Receiving ISS Ham TV
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This forum is run by the BATC (British Amateur Television Club), it is service made freely available to all interested parties, please do not abuse this privilege.
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This forum is run by the BATC (British Amateur Television Club), it is service made freely available to all interested parties, please do not abuse this privilege.
Thank you
Re: Receiving ISS Ham TV
Tracked two passes tonight, one south and one north of this QTH.
Similar shape to the Goonhilly dish except they had video for twice as long!
For info my dish is 1.1M
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For info my dish is 1.1M
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Re: Receiving ISS Ham TV
I'm shure that tree has got bigger! 
Just shows you don't need a perfect site, this is almost a /P installation! 
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Tracking ISS Ham TV using a Cheap Rotator
I have built a system to track and receive the ISS Ham TV transmissions using a single, inexpensive, rotator. It will easily give 2 and a half minutes of solid video on a typical pass using a 60cm dish and the receiver described in CQ-TV and here: http://www.batc.org.uk/forum/viewtopic. ... 389#p10138.
The system uses the assumption that the ISS follows a linear arc across the sky on each pass. All that is then required is to pre-position the rotator and dish so that it can track the ISS as it traverses the arc. In practice, the maximum error in this assumption is less than 2 degrees - no problem for a 60cm dish with 12 degrees beamwidth.
System Description
The dish is fixed exactly at right angles to the stub mast at the "top" of the rotator. The rotator mast is tilted so that the dish points directly at the ISS when the ISS is nearest to overhead (apogee). So, for a pass where the ISS rises to 86 degrees in the sky, the mast is tilted 4 degrees up from the horizontal.
The azimuth orientation of the mast is critical. I orientate the mast so that it aligns with the mid-point between the ISS azimuth at 30 degrees elevation rising, and its azimuth at 30 degrees elevation setting.
Lastly, a means is required to rotate the dish to track the ISS on the arc during the pass. I modified my rotator controller and added relays controlled by a Raspberry Pi. I also put a feedback potentiometer at the rotator to measure the exact dish position. A Python program runs on the Raspberry Pi which checks the time, reads the desired position from a text file, and then moves the dish until the measured position is correct.
The text file of desired position is derived by downloading the latest ISS tracking elements from the web, calculating the azimuth and elevation for every second during the pass, and then manually performing a coordinate transformation (in Excel) to calculate the desired rotator angle for each second.
The disadvantage of this system is that the mast needs to be pre-positioned exactly for each pass - but with Tim Peake using the camera for one pass a week (we hope), this is practical. I will post more details as I refine the system.
Dave
G8GKQ
The system uses the assumption that the ISS follows a linear arc across the sky on each pass. All that is then required is to pre-position the rotator and dish so that it can track the ISS as it traverses the arc. In practice, the maximum error in this assumption is less than 2 degrees - no problem for a 60cm dish with 12 degrees beamwidth.
System Description
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- IMG_0658.JPG (148.07 KiB) Viewed 9754 times
The azimuth orientation of the mast is critical. I orientate the mast so that it aligns with the mid-point between the ISS azimuth at 30 degrees elevation rising, and its azimuth at 30 degrees elevation setting.
Lastly, a means is required to rotate the dish to track the ISS on the arc during the pass. I modified my rotator controller and added relays controlled by a Raspberry Pi. I also put a feedback potentiometer at the rotator to measure the exact dish position. A Python program runs on the Raspberry Pi which checks the time, reads the desired position from a text file, and then moves the dish until the measured position is correct.
The text file of desired position is derived by downloading the latest ISS tracking elements from the web, calculating the azimuth and elevation for every second during the pass, and then manually performing a coordinate transformation (in Excel) to calculate the desired rotator angle for each second.
The disadvantage of this system is that the mast needs to be pre-positioned exactly for each pass - but with Tim Peake using the camera for one pass a week (we hope), this is practical. I will post more details as I refine the system.
Dave
G8GKQ
Re: Receiving ISS Ham TV
Just need some rope and a motorised winch, then you have a full tracking system 
Good work.
Rob
M0DTS
Good work.
Rob
M0DTS
Re: Receiving ISS Ham TV
Definitely one of those, why didn't I think of that ideas.
- Charles
- Charles
Re: Receiving ISS Ham TV
Using my simple ISS tracker and a 60cm dish, I have just received 3 minutes 40 seconds of video from Ham TV. That's about the limit imposed by the buildings surrounding my garden.
Interested to hear how other stations get on with small dishes.
Dave
G8GKQ
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Dave
G8GKQ
Re: Receiving ISS Ham TV
Well done to all those involved with Tim Peake's first HamTV activation.
A video of the event as received at my QTH in Bournemouth on 11/02/16 is here https://youtu.be/9keVA21DPBc
The ARISS contact was with the Royal Masonic School for Girls in Rickmansworth, Hertfordshire.
A video of the event as received at my QTH in Bournemouth on 11/02/16 is here https://youtu.be/9keVA21DPBc
The ARISS contact was with the Royal Masonic School for Girls in Rickmansworth, Hertfordshire.
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Re: Receiving ISS Ham TV
VLC screen capture direct from the .ts file
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Re: Receiving ISS Ham TV
But what is that stuck to his forehead? Insulating tape? Answers on a postcard please.